Studies of mortality deceleration sometimes use the order of deceleration between two groups - such as birth cohorts or subpopulations defined by race or sex - to draw conclusions about population heterogeneity. These studies often draw on the fact that between two closed groups, ceteris paribus, the higher-mortality group will decelerate at a younger age. This paper gives a first consideration to the order of deceleration between open groups. I construct a model with a one-way flow from 'healthy' to 'sick' status and, crucially, assume that a subset of the cohort has elevated risk for both sickness and death. Using simulations designed to resemble, in the aggregate, cohorts in the Human Mortality Database, I show that mortality deceleration order in such a cohort is essentially unpredictable because it depends on the interaction between a large number of parameters, some of which are unobserved in empirical data. These results suggest that it may be challenging to extend the study of mortality deceleration to include open groups whose memberships are selected for frailty or robustness, while still drawing meaningful conclusions about population heterogeneity.

Modal age at death: lifespan indicator in the era of longevity extension

Shiro Horiuchi, (correspondence author), CUNY School of Public Health, CUNY Institute for Demographic Research, City University of New York, USA. shoriuch(at)hunter.cuny.eduNadine Ouellette, Institut National d'Études Démographiques (INED), FranceSiu Lan Karen Cheung, Sau Po Centre on Ageing and Department of Social Work and Social Administration, The University of Hong Kong, Hong Kong SARJean-Marie Robine, Institut National de la Santé et de la Recherche Médicale (INSERM), Health and Demography, France

This paper examines and demonstrates the importance of the adult modal age at death (M) in longevity research. Unlike life expectancy at birth (e0) and median age at death, M is determined solely by old-age mortality as far as mortality follows a bathtub curve. It represents the location of old-age death heap in the age distribution of deaths, and captures mortality shifts more accurately than conditional life expectancies such as e65. Although M may not be directly determined from erratic mortality data, a recently developed method for deriving M from the P-spline-smoothed mortality curve based on penalised Poisson likelihood is highly effective in estimating M. Patterns of trends and differentials in M can be noticeably different from those in other lifespan measures, as indicated in some examples. In addition, major mathematical models of adult mortality such as the Gompertz, logistic and Weibull models can be reformulated using M, which plays a critical role as the mortality level parameter in those models.

Human beings have always been fascinated by super-longevity and now, as mortality declines to levels never before experienced, living to be a centenarian becomes a real, though still a rather remote, possibility. In most countries of the industrialised world the modal age at death is rising constantly and the number of centenarians is growing exponentially. A growing corpus of research is focussing on the centenarians, their particularities and the verification of their centenarian status. However, if we wish to unravel the secrets for attaining this magnificent age, we need to look beyond the centenarian communities themselves. The number of people becoming centenarians is determined by three different processes: the numbers born 100 years earlier, the probability of reaching old age and the probability of surviving old age to become a centenarian. Mortality up to age 80 and mortality beyond age 80, though loosely related, need to be treated as qualitatively different phenomena. However, there have been few studies of conditions distinguishing between populations and societies with low and high mortality at old ages. Instead, most work has focussed on identifying and carefully documenting high longevity populations, those with an unusually high number of centenarians - usually small, bounded populations - while no attention has been given to their complement, high shortivity populations, those with a lack of centenarians. In the absence of a theory of population longevity and shortivity, we cannot distinguish between populations which are genuinely different from most others, and those which are merely chance outliers. The critical question is thus 'what are the transition mechanisms'? We need to focus less on the centenarians themselves, and more on the conditions which distinguish populations with a relatively high probability of surviving from age 80 to age 100 from those with a relatively low probability of survival.

The aim of this study was to compare the level of population longevity and the characteristics of four geographic areas where unusually high proportions of long-lived individuals have been observed. For these areas (Ogliastra in Sardinia, Okinawa in Japan, the Nicoya peninsula in Costa Rica and the island of Ikaria in Greece). The term of 'blue zone' (BZ) given to these areas is defined as a limited region where the population shares a common lifestyle and environment and whose exceptional longevity has been accurately verified. This paper discusses the use of different indexes to measure the longevity of a population. As a preliminary result of our investigations we confirm the exceptional level of male longevity in the Sardinian BZ and both male and female longevity in Okinawa. Considering possible explanations, we observed that BZ populations are geographically and/or historically isolated (islands and mountainous regions). These populations succeeded in maintaining a traditional lifestyle implying an intense physical activity that extends beyond the age of 80, a reduced level of stress and intensive family and community support for their oldest olds as well as the consumption of locally produced food. This is likely to have facilitated the accumulation of ideal conditions capable of limiting the factors that negatively impact on health in most Western populations. These people experienced the epidemiological transition - and its implications - in relative recent times, and their remarkably good health status during ageing could be the result of a delicate balance between the benefits of the traditional lifestyle and those of modernity (increased wealth, better medical care). All these factors could have promoted an ideal milieu for the emergence of long-lived phenotypes at the population level.

Reliable data show that the Nicoyan region of Costa Rica is a hot spot of high longevity. A survival follow-up of 16,300 elderly Costa Ricans estimated a Nicoya death rate ratio (DRR) for males 1990-2011 of 0.80 (0.69-0.93 CI). For a 60-year- old Nicoyan male, the probability of becoming centenarian is seven times that of a Japanese male, and his life expectancy is 2.2 years greater. This Nicoya advantage does not occur in females, is independent of socio-economic conditions, disappears in out-migrants and comes from lower cardiovascular (CV) mortality (DRR = 0.65). Nicoyans have lower levels of biomarkers of CV risk; they are also leaner, taller and suffer fewer disabilities. Two markers of ageing and stressâ€”telomere length and dehydroepiandrosterone sulphate - are also more favourable. The Nicoya diet is prosaic and abundant in traditional foods like rice, beans and animal protein, with low glycemic index and high fibre content.

In investigating processes of demographic change such as the longevity revolution, vanguard populations are of specific interest, as studying them is likely to improve our understanding of the underlying mechanisms driving the change. This paper explores the spatial variation in the occurrence of exceptional longevity in Germany using a large individual-level dataset covering all persons who reached ages of 105 and above in Germany in the period 1991 to 2002 (N: 1,339). The first part of our analysis reveals that many of these individuals died very close to their birth place. This finding of a localised lifetime net migration pattern supports the view that an analysis of regional variation in exceptional longevity can produce meaningful results, as a large share of the individuals were living in the same spatial context, at least early and late in life. In our analysis of regional variation in exceptional longevity, we could detect consistent hot spots in Berlin and north-western Germany. These findings are all the more notable as the areas of highest life expectancy at birth are currently located in the south of Germany.

Richard G. Rogers (correspondence author), Population Program, University of Colorado, USA. richard.rogers(at)colorado.eduPatrick M. Krueger, Department of Health and Behavioral Sciences, University of Colorado, USARichard Miech, Survey Research Center, University of Michigan, USAElizabeth M. Lawrence, Department of Sociology and Population Program, IBS, University of Colorado, USA

We examine variability in mortality risk among heterogeneous nondrinking statuses. We employ Cox proportional hazard models and the United States National Health Interview Survey-Linked Mortality Files (NHIS-LMF) to examine the risk of death associated with drinking and nondrinking statuses, net of demographic, socio- economic, behavioural, health and geographic factors. Mortality risk is low for light drinkers and many individuals who abstain from drinking - including those who abstain for religious and moral reasons, have a responsibility to family, were brought up not to drink and are not social. Mortality is higher among former, infrequent and moderate drinkers, and among individuals who abstain because they do not like the taste of alcohol, are concerned that they will lose control or are concerned about adverse consequences. Unsurprisingly, mortality risk is by far the highest for heavy drinkers. Our results show that reasons for abstention capture heterogeneity in the risk of death among lifetime abstainers.

This study addresses the mortality of the members of the Saxonian Academy of Sciences and Humanities in Leipzig. In fact, learned societies have been shown to present vanguard groups in the achievement of longevity. We use biographical records from the members of the Saxonian Academy of Sciences from 1846 to 2010 and compare their mortality to German life table estimates, where particularly attention is paid to the mortality differentials between eastern and western Germany. The Saxonian academicians show indeed a higher life expectancy at age 60 than the general German male population, where the latter gap has been widening since the 1950s. Comparing the life expectancy values for the Saxonian academicians to available estimates of various European learned societies yields a similar longevity, suggesting that the survival of the academicians is less determined by national mortality conditions but that academicians rather share a common health advantage.

It is well established that cigarette use contributes to an extraordinary increase in the risk of mortality. Nevertheless, a small proportion of long-term chronic smokers manage to reach extreme old age, potentially suggesting that this sub-population may have distinct biological protection or repair mechanisms that allow it to better cope with the hazards of smoking. Using data from the Third National Health and Nutrition Examination Survey (NHANES III), on 5,423 adults aged 50 and over, we examined how among smokers and never-smokers mortality differs over the age range and whether smoking-related differences in markers of physiological functioning converge with increasing age. Our findings suggest that differences in mortality risk between current smokers and those who have never smoked are significantly less pronounced at older ages, and that smoking did not significantly contribute to subsequent mortality risk for individuals who had survived to at least age 80. Furthermore, among those who were less than 80 years of age, smokers had significantly elevated levels of inflammation in comparison to never-smokers, there were no such differences found between smokers and never-smokers at age eighty and above. Finally, we found a crossover effect for HDL cholesterol - with smokers showing worse levels at younger ages than never-smokers and better levels, although not significant, at older ages. Our study presents evidence that long-lived smokers may represent a distinct and biologically advantaged group, who are less susceptible to the negative side effects of smoking and perhaps other environmental insults.

Russians experience higher adult mortality than Central Asians despite higher socioeconomic status. This study exploits Kazakhstan's demographic and geographic diversity to study ethnic differences in cause-specific mortality. In multivariate regression, all-cause mortality rates for Russian men is 27% higher than for Kazakh men, and alcohol-related death rates among Russian men are 2.5 times higher (15% and 4.1 times higher for women, respectively). Significant mortality differentials exist by ethnicity for external causes and alcohol-related causes of death. Adult mortality among Kazakhs is higher than previously found among Kyrgyz and lower than among Russians. The results suggest that ethnic mortality differentials in Central Asia may be related to the degree of russification, which could be replicating documented patterns of alcohol consumption in non-Russian populations.

The aims of this study are to analyse the two-way association between women fertility and longevity, and parental transmission of longevity. The wealth of information gathered in the AKeA2 demographic survey on Sardinian centenarians-have been used by applying Logistic Regression Models. For the association between longevity and fertility, we find evidence that long livers benefit from factors related to the timing of fertility (in particular the age at birth of the last child) that the literature suggests may foster longevity. Regarding the association with parental transmission, it seems to have significant effects for women but not for men. We always found that a higher birth order decreases the probability of becoming a centenarian. There is a negative effect of a higher father age at birth on the longevity of female offspring. The latter suggests that long-lived women seem to have been favoured both by their own late fertility and young paternal age at the moment of their own procreation.

The literature provides increasing empirical support for the idea that early-life experiences can greatly shape someone's future health and longevity. Besides shared early-life conditions, within-family variation in maternal age at time of childbirth and birth order have been found to be related to later-life survival. In this study, we examine whether there is a persisting effect of maternal age and birth order on survival to age 104 when both variables are considered and adjusted for season of birth and birth spacing. To address potential confounding by unmeasured family-level factors, we apply a case-sibling control analysis. Using data on 273 centenarians born in Quebec in the 1890-1900 period and their siblings, we show that children born to mothers over age 40 are less likely to reach age 104 while third- and fourth-born children are more likely to make this landmark. When examining the effect of maternal age in combination with the effect of birth order, we obtain higher estimates of both maternal age effects and birth order effects, indicating that the measured influence of one is suppressed when the other is not accounted for. We argue that being born early in the sibling row may provide a biological advantage related in part to the quality of the female reproductive system, but this effect may be counterbalanced by the precariousness of the family as a socio-economic unit at the earliest stages of its cycle. No mediation of these effects is seen when including birth spacing and season of birth. However, we find that birth order differences in longevity are most prominent among siblings born to older mothers and in families where the father was a farmer. We discuss other possible social and historical pathways through which maternal age, birth order and season of birth may operate to mould the offspring's longevity.

Leonid A. Gavrilov (correspondence author), Center on Aging, NORC at the University of Chicago, USA. gavrilov(at)longevity-science.orgNatalia S. Gavrilova, Center on Aging, NORC at the University of Chicago, USA

Studies of centenarians are useful in identifying factors leading to long life and avoidance of fatal diseases. In this article we consider several approaches to study effects of early-life and midlife conditions on survival to advanced ages: use of non-biological relatives as controls, the within-family analysis, as well as a sampling of controls from the same population universe as centenarians. These approaches are illustrated using data on American centenarians, their relatives and unrelated shorter-lived controls obtained from the online genealogies. The within-family analysis revealed that young maternal age at person's birth is associated with higher chances of exceptional longevity. Comparison of centenarians and their shorter-lived peers (died at age 65 and sampled from the same pool of online genealogies) confirmed that birth timing in the second half of the calendar year predicts survival to age 100. Parental longevity as well as some childhood and midlife characteristics also proved to be significant predictors of exceptional longevity.

This study investigates the role of familial transmission on individual survival in an inland community of Sardinia that stands for the exceptional longevity of its inhabitants. The analysis considers the complete survival trajectories of individuals born in the village of Villagrande Strisaili from unions in the period from 1850 to 1910 and aims to estimate the possible effect on the relationships parentâ€“offspring and between siblings. Our results show that the frail familial component of the population, rather than the robust one, proves to be a good predictor of individual survival. No association between father survival and that of children was found. Having instead a long-living mother increases lifespan, especially for daughters. But the strongest relationship is that observed between siblings. The survival of siblings is positively associated with individual survival and this relationship is particularly strong for males. This finding points for both genetic and environment influence, and particularly of early-life conditions, on longevity.